Valve seat construction



Oct. 22, 1963 E. V6GEL l 3,107,895

VALVE SEAT CONSTRUCTION Filed Sept. 10, 1959 United States Patentassiyor Winterthur, Switz- Filed Sept. 10, 1959, Ser. No. 839,118priority, application Switzerland Sept. 11, 1958 4 Claims. (Cl. 251359)Claims This invention relates to a valve With a seat element bearing ona supporting surface of the valve housing, which seat element has aseating face for a valve body performing the opening and closing motion.

According to this invention, the seat element is pressed against asupporting surface provided in the valve housing by an elasticintermediate piece welded to form a sealed joint and under initialstress between the seat element and the valve housing. In the process ofmanufacturing a valve according to the invention, the seat element andthe elastic intermediate piece are welded together, then insertedjointly until the valve seat element strikes against the supportingsurface, after which the intermediate piece is put under initial stressby means of a tensioning device and welded to the housing.

Because of the initial stress of the elastic intermediate piece actingon it, the seat element cannot be lifted from its supporting surface orbe brought into an undesired slanted position, as can be the case, forexample, if the seat element is welded directly to the valve housing. Ina construction of the known type in which the valve seat element iswelded directly to the valve housing, thermal stresses occur sometimesduring the welding of the seat element to the valve housing since it isnot possible to weld uniformly over the entire joint. Besides, the seatelement is heated more during the welding than the housing and thereforecontracts more on cooling after welding than the housing. For thisreason, the seat element of known construction detaches itself sometimesfrom the supporting surface during the cooling and moves into a more orless slanted position, so that the valve body does not seat properly andthe valve is leaky or untight from the start. According to theinvention, inaccuracies of craftsmanship, as they occur occasionally inwelding, are also avoided. The seat element, even if one of the weldingsshould not be exact, has always its exact position necessary for thecompletely tight seating of the valve body on its seat in closedposition of the valve. This is due to the elastic intermediate piecethat equalizes all inaccuracies because of its initial stress, and thisexact position is maintained even after prolonged use.

An object of this invention is to provide a valve in which the seatelement is accurately positioned and se cured on a support therefor inthe valve housing.

Another object of this invention is to provide a valve in which the seatelement is pressed against its support by an elastic element welded tothe seat element and to the housing.

In the drawing:

The single FIGURE is a sectional view of an embodiment of a valveaccording to this invention, with the valve body omitted.

The valve, assembled in a water supply line 22, 23 for regulating thesteam temperature of a boiler plant by the addition of water, comprisesa valve housing 7 in which a supporting surface 8 for a valve seatelement 1 is provided. The seat element 1 bears with its lower endsurface 9 on the supporting surface 8 and carries on the opposite upperend surface at 2 a seating surface 14 which is made, for example, of analloy known by the name of Stellite, which consists substantially ofcobalt and chromium. Against the seating surface 14 is pressed in closedposition a valve body (not shown) which performs the opening and closingof the valve.

The seat element 1 has a surrounding flange 13 having a lower surface 12which is relatively close to the lower end surface 9. As shown, theflange is tightly welded at 3 to a bellows-like elastic intermediatepiece or element 4. The other end of the element 4 is tightly welded at5 to a lip 6 of the valve housing 7, with the element 4 under initialstress. Due to the stress of the element 4, the seat element 1 isconstantly pressed with its end surface 9 against the supporting surface8 of the housing so that the seating surface 14 maintains its correctposition, the valve body is properly seated, and the valve remainsconstantly tight in closed position.

Before the parts are assembled, the seat element 1 and the elasticelement 4 are tightly welded together at 3 while outside the housing.Then the assembled parts 1 and 4 are inserted, as shown in the drawing,from the top jointly into the housing 7 until the surfaces 9 and 12strike against the supporting surface 8 and the surface of the housingopposite surface 12. Then a spindle 10 provided with a disk-shaped head15 is inserted from the top. After interposing a spring '11 and a washer18, a nut 21 is screwed on the lower thread 19 of the spindle 10 and theresilient or elastic element 4 is brought to the desired initial stressby tightening the nut 21. The initial stress can be read from apreviously calibrated measuring scale 20, for example in kgs., and canbe of the order of to 500 kgs. In this position, with the seat elementpressed against its supporting surface in the housing by the stressedelastic piece 4, the element 4 is welded at 5 to the lip 6. Then the nut21 is loosened and the parts 18, 11,

10 are removed. Subsequently the valve body (not shown) cooperating withthe seating surface 14 is inserted.

During operation of equipment with which the valve is used, steam of 500to 600 C., for example, and 300 atrn. flows through a line (nots hown)to which water of 300 C., for example, and a corresponding excesspressure can be added through the line 22, 23 by opening the valve, sothat the temperature of the steam can be regulated.

The valve can naturally also be used in other installations.

Having described my invention, I claim:

-1. In a valve, a valve housing having a valve chamber therein, inletand outlet passages disposed in said valve housing and communicatingthrough said valve chamber,

' a supporting surface disposed in one end of said valve chamber, a seatelement disposed in said valve chamber, said seat element including alower end abutting against said supporting surface, an upper endcontaining a seating surface, and a flange portion adjacent said lowerend, an intermediate elastic tubular member disposed in said valvechamber having one end abutting against said flange portion to applyuniform annular pressure thereon, the other end of said intermediateelastic tubular member being disposed adjacent the other end of saidvalve chamber while being under stress to press said lower end of saidseat element into permanent sealing engagement against said supportingsurface of said valve chamber, and means to secure the other end of saidintermediate elastic tubular member to the other end of said valvechamber so that said seating surface maintains its correct position.

2. In a valve according to claim 1 in which said one of saidintermediate elastic member is secured to said flange portion by adeposit of weld and saidrneans to secure the other end of saidintermediate elastic member to the other end of said valve chamberconsists of a deposit of weld.

3. In a valve according to claim 1 in which a further supporting surfaceis disposed in the one end of said valve chamber adjacent saidsupporting surface, said flange portion abutting against said furthersupporting surface.

4. In a valve according to claim 1 in Which said intermediate elastictubular member has a bellows-like configuration. 5

References (Jited in the file of this patent UNITED STATES PATENTS647,192 Lunken Apr. 10, 19110 10 4 Murray Oct. 22, 1929 Cram Dec. 17,1940 Venton Nov. 4, 1941 Eplett May 2, 1944 Ellis Sept. 6, 1958Bredtschneider May 19, 1959 FOREIGN PATENTS Great Britain of 1939

1. IN A VALVE, A VALVE HOUSING HAVING A VALVE CHAMBER THEREIN, INLET ANDOUTLET PASSAGES DISPOSED IN SAID VALVE HOUSING AND COMMUNICATING THROUGHSAID VALVE CHAMBER, A SUPPORTING SURFACE DISPOSED IN ONE END OF SAIDVALVE CHAMBER, A SEAT ELEMENT DISPOSED IN SAID VALVE CHAMBER, SAID SEATELEMENT INCLUDING A LOWER END ABUTTING AGAINST SAID SUPPORTING SURFACE,AN UPPER END CONTAINING A SEATING SURFACE, AND A FLANGE PORTION ADJACENTSAID LOWER END, AN INTERMEDIATE ELASTIC TUBULAR MEMBER DISPOSED IN SAIDVALVE CHAMBER HAVING ONE END ABUTTING AGAINST SAID FLANGE PORTION TOAPPLY UNIFORM ANNULAR PRESSURE THEREON, THE OTHER END OF SAIDINTERMEDIATE ELASTIC TUBULAR MEMBER BEING DISPOSED ADJACENT THE OTHEREND OF SAID VALVE CHAMBER WHILE BEING UNDER STRESS TO PRESS SAID LOWEREND OF SAID SEAT ELEMENT INTO PERMANENT SEALING ENGAGEMENT AGAINST SAIDSUPPORTING SURFACE OF SAID VALVE CHAMBER, AND MEANS TO SECURE THE OTHEREND OF SAID INTERMEDIATE ELASTIC TUBULAR MEMBER TO THE OTHER END OF SAIDVALVE CHAMBER SO THAT SAID SEATING SURFACE MAINTAINS ITS CORRECTPOSITION.